Fresh water tank unit for portable toilet



FIG. 1 is a left, front perspective view of a fresh water tank unit for a portable toilet showing my new design, on a reduced scale, the broken line drawing of a toilet and housing is for illustrative purposes only and forms no part of the claimed design;

FIG. 2 is a left front perspective view thereof;

FIG. 3 is a left rear perspective view thereof;

FIG. 4 is a right rear perspective view thereof; and,

FIG. 5 is a right front perspective view thereof. 

The ornamental design for a fresh water tank unit for a portable toilet, as shown and described. 